CO2 Sensor Polymer Matrix for IC Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing integrated circuits (ICs) face challenges in cost-effectively integrating carbon dioxide (CO2) sensors with high ppm sensitivity, particularly in mass market applications like HVAC, where CO2 levels are below 1,000 ppm, due to the difficulty in integrating CO2-binding organic liquids (CO2-BOLs) as sensor materials.
Innovation Solution
An integrated circuit with a CO2 sensor comprising a semiconductor substrate, a pair of electrodes, and a CO2-permeable polymer matrix encapsulating a solution of organic alcohol and amidine or guanidine base, where the polymer matrix is formed using a gel-forming block co-polymer with a rigid and elastomeric block, allowing for immobilization of CO2-BOL and enabling ppm CO2 sensitivity without additional chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CO2-binding organic liquids (CO2-BOLs) are integrated as sensor materials on ICs, then CO2 sensitivity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses a porous polymer matrix as a support structure that allows CO2 to diffuse through while containing the CO2-BOL. The porous structure provides both mechanical stability and selective permeability, enabling CO2 molecules to reach the sensing liquid phase while maintaining sensor integrity on the IC substrate.
Solution Approach 2:
The patent creates a composite sensor system combining the CO2-BOL (liquid sensing material) with a porous polymer matrix (solid support structure). This composite approach allows the liquid CO2-BOL to maintain its high sensing performance while the solid matrix provides mechanical stability and ease of integration on the IC, resolving the contradiction between sensitivity and manufacturing complexity.
2Measurement precision
If neat CO2-BOL is used for high CO2 uptake capacity, then measurement precision is improved, but stability and longevity deteriorate due to evaporation and degradation
Solution Approach 1:
The porous polymer matrix acts as a containment structure that holds the neat CO2-BOL while allowing CO2 diffusion. The porous structure provides surface area for sensing while preventing bulk liquid evaporation, maintaining both high CO2 uptake capacity and long-term stability.
Solution Approach 2:
The polymer matrix forms a thin film or shell structure that encapsulates the CO2-BOL. This flexible yet stable matrix allows CO2 permeation while providing a protective barrier against environmental degradation and uncontrolled evaporation, ensuring sensor reliability.
3Measurement precision
If ppm-level CO2 sensitivity is achieved, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The porous polymer matrix serves multiple functions simultaneously: it provides mechanical support, enables CO2 diffusion, contains the CO2-BOL, and facilitates integration on the IC substrate. This multi-functionality reduces the need for additional components and manufacturing steps, lowering overall production cost while maintaining ppm-level sensitivity.
Solution Approach 2:
The porous structure of the polymer matrix is inherently suitable for gas sensing applications, providing high surface area to volume ratio that enhances ppm-level detection capability. The standard porous polymer materials are also cost-effective and readily available, making the sensor manufacturable at scale.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables cost-effective integration of a CO2 sensor with high sensitivity on ICs, maintaining responsiveness and stability over time by using physically cross-linking polymers like Kraton G1650, which retains CO2-BOL and maintains sensor performance across varying CO2 levels and relative humidity.
Implementation Method 1
a CO2-permeable polymer matrix at least partially covering the pair of electrodes, said matrix encapsulating a solution comprising an organic alcohol; and an amidine or guanidine base
Implementation Method 2
David J. Heldebrandt et al. in Energy Procedia 1 (2009), pages 1187-1195 disclose a new class of CO2 absorbing materials, referred to as CO2-binding organic liquids (CO2-BOLs) that are neat (solvent-free) liquid mixtures of organic alcohols and organic amidine or guanidine bases, which undergo the following reversible reaction in the presence of CO2
Data Source
AI summary
Disclosed is an integrated circuit (100) comprising a semiconductor substrate (110) carrying a plurality of circuit elements (111); and a carbon dioxide sensor (120) over said semiconductor substrate, said sensor comprising a pair of electrodes (122, 124) laterally separated from each other; and a carbon dioxide (CO2) permeable polymer matrix (128) at least partially covering the pair of electrodes, said matrix encapsulating a liquid (126) comprising an organic alcohol and an organic amidine or guanidine base. A composition for forming such a CO2 sensor on the IC and a method of manufacturing such an IC are also disclosed.